﻿
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<!-- saved from url=(0014)about:internet -->
<html xmlns:msxsl="urn:schemas-microsoft-com:xslt" xmlns:mssdk="winsdk" xmlns:script="urn:script" xmlns:build="urn:build" xmlns:MSHelp="http://msdn.microsoft.com/mshelp">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8"/>
<meta name="Description" content="Identifying the Caller From the Server Thread"/>
<meta name="MSHAttr" content="PreferredSiteName:MSDN"/>
<meta name="MSHAttr" content="PreferredLib:/library/windows/hardware"/>
<title>Identifying the Caller From the Server Thread</title>

<meta name="MS-HAID" content="t11_rpc_acpi_045ac5d9-af8d-48d9-bcfa-0fd3fe2d1a60.xml"/>


<link rel="STYLESHEET" type="text/css" HREF="../common/backsdk4.css"/>





<style>
html,div { margin: 0; padding: 0;}

body {
	padding: 0px;
	margin: 0px;
	overflow: auto;
	height: 100%;
}

#winchm_template_button{
	float: right;
	width: 93px;
	top: 7px;
	position: relative;
	text-align: right;
	right: 5px;
	height: auto;
}

#winchm_template_top{
	padding: 0px;
	margin: 0px;
	border-bottom: 1px solid #9B9B9B;
	background-color: #B1CEFE;
}

#winchm_template_navigation{
	margin: 0px;
	padding-top: 7px;
	padding-left: 7px;
	padding-bottom: 3px;
	padding-right: 0px;
	font-size: 8.5pt;
	font-family: Arial, Helvetica, sans-serif;
	font-weight: normal;
	color: #585858;
}

#winchm_template_title{
	margin: 0px;
	padding-top: 4px;
	padding-left: 7px;
	padding-bottom: 7px;
	padding-right: 0px;
	font-size: 18px; 
	font-family: Verdana, Geneva, sans-serif;
	color: #363636;
}

#winchm_template_content{
	margin-top: 20px;
	margin-left: 15px;
	margin-bottom: 20px;
	margin-right: 15px;
	width: auto  !important;
	width: 100%;
}

#winchm_template_footer{
	border-width: 1px;
	border-color: #B1CEFE;
	border-top-style: solid;
	margin-top: 15px;
	margin-left: 15px;
	margin-bottom: 20px;
	margin-right: 15px;
	padding-top: 7px;
	padding-left: 0px;
	padding-bottom: 0px;
	padding-right: 0px;
	font-family: arial, helvetica, sans-serif;
	font-size: 8.5pt;
	color: #696969;
	width: auto;
	text-align: left;
}


#winchm_template_container{
	margin: 0px;
	padding: 0px;
	position: static;
	padding-bottom: 3px;
	overflow: auto;
	background-color: #FFFFFF;
}


@media print
{
#winchm_template_container{
	position: static;	
	margin: 0px;
	padding: 5px;
	
	width: auto;
	height: auto;
	overflow: auto;
}
#winchm_template_button{
visibility:hidden;
}
}

#winchm_template_navigation A:link	{text-decoration: none; color:#004080}
#winchm_template_navigation A:visited  {text-decoration: none; color: #004080}
#winchm_template_navigation A:active {text-decoration: none; color: #004080 }
#winchm_template_navigation A:hover {text-decoration: none;color: #0080FF}

A:link	{text-decoration: underline; color:#0033CC}
A:visited  {text-decoration: underline; color: #0033CC}
A:active {text-decoration: underline; color: #0033CC }
A:hover {text-decoration: underline;color: #FF0000;}
</style>
<script type="text/javascript">
function isMobile(){
Agent = window.navigator.userAgent;
if (Agent.indexOf("iPhone")>=1 || Agent.indexOf("iPad")>=1 || Agent.indexOf("iPod")>=1 || Agent.indexOf("Android")>=1){
return true;
}else{
return false;	
}

}
function d_onresize(){
if (window.navigator.userAgent.indexOf("MSIE")>=1){
document.getElementById('winchm_template_container').style.pixelWidth = document.body.offsetWidth - 3;
document.getElementById('winchm_template_container').style.pixelHeight = document.body.offsetHeight - document.getElementById('winchm_template_top').offsetHeight - 4;
}
document.getElementById('winchm_template_container').style.top = document.getElementById('winchm_template_top').offsetHeight + 'px';
}

function d_onbeforeprint(){
document.getElementById('winchm_template_container').style.width = 'auto';
document.getElementById('winchm_template_container').style.height = 'auto';
}

function d_onafterprint(){
d_onresize();
}

if(!isMobile()){

window.onload = d_onresize;
window.onresize = d_onresize;
window.onbeforeprint = d_onbeforeprint;
window.onafterprint = d_onafterprint;

document.write("<style>\n");
document.write("body {overflow: hidden;}\n");
document.write("#winchm_template_container {position: absolute;overflow: auto;top : 0px;right: 0px;bottom: 0px;left: 0px;}\n");
document.write("</style>\n");
}

</script>
</head>
<body><script language="JavaScript" type="text/JavaScript">
function syn(){
if(parent.nav.tree){
 if(parent.nav.tree.loaded){
  parent.nav.tree.selectNode(1446);
 }else{
  setTimeout("syn()",500);
}
  }else{
  setTimeout("syn()",500);
  }}
if(parent!=self){
  setTimeout("syn()",100);
}else{
  parent.location.href = "../../index.htm?page=debugger/identifying_the_caller_from_the_server_thread.htm";
}
originalOnload = window.onload;
if(originalOnload==null){
window.onload = function(){parent.contentLoaded = true;};
}else{
window.onload = function(){originalOnload();parent.contentLoaded = true;};
}
</script> 


<div id="winchm_template_top">
	<div id="winchm_template_button"><A href="checking_for_stuck_threads.htm" title="Previous topic"><img id="winchm_template_prev" alt="Previous topic" src="../template2/btn_prev_n.gif" border="0"></a><A href="rpc_state_information_internals.htm" title="Next topic"><img id="winchm_template_next" alt="Next topic" src="../template2/btn_next_n.gif" border="0"></a></div>
	<div id="winchm_template_navigation">Help &gt; 
<A href="introduction6.htm">Debugging Tools for Windows (WinDbg, KD, CDB, NTSD)</A> &gt; <A href="debugging_techniques.htm">Debugging Techniques</A> &gt; <A href="specialized_debugging_techniques.htm">Specialized Debugging Techniques</A> &gt; <A href="rpc_debugging.htm">RPC Debugging</A> &gt; <A href="common_rpc_debugging_techniques.htm">Common RPC Debugging Techniques</A> &gt; </div>
	<div id="winchm_template_title">Identifying the Caller From the Server Thread</div>
</div>
<div id="winchm_template_container">
	<div id="winchm_template_content"><div id="mainSection"><p>It is possible to determine what made a given RPC call, even if the only information you have is the server thread that serviced the call.</p>
<p>This can be very useful -- for example, to find out who passed invalid parameters to an RPC call.</p>
<p>Depending on which protocol sequence is used by this particular call, you can get varying degrees of detail. Some protocols (such as NetBios) do not have this information at all.</p>
<p class="proch"><img src="../common/wedge.gif" alt=""/><b>Identifying the caller from the server thread
     </b></p>
<ol>
<li>
<p>Start a user-mode debugger with the server thread as the target.</p>
</li>
<li>Get the process ID by using the <a href="#Bookmark1960"><b>| (Process Status)</b></a> command:<div class="code"><span codelanguage=""><table>
<tr>
<th></th>
</tr>
<tr>
<td>
<pre>0:001&gt; |
  0     id: 3d4 name: rtsvr.exe</pre>
</td>
</tr>
</table></span></div>
</li>
<li>Get the active calls in this process by using the <a href="#Bookmark2661"><b>!rpcexts.getcallinfo</b></a> extension. (See the reference page for an explanation of the syntax.) You need to supply the process ID of 0x3D4:<div class="code"><span codelanguage=""><table>
<tr>
<th></th>
</tr>
<tr>
<td>
<pre>0:001&gt; !rpcexts.getcallinfo 0 0 FFFF 3d4
Searching for call info ...
PID  CELL ID   ST PNO IFSTART  THRDCELL  CALLFLAG CALLID   LASTTIME CONN/CLN
----------------------------------------------------------------------------
03d4 0000.0004 02 000 19bb5061 0000.0002 00000001 00000001 00a1aced 0000.0003</pre>
</td>
</tr>
</table></span></div>
<p>Look for calls with status 02 or 01 (dispatched or active). In this example, the process only has one call. If there were more, you would have to use the <a href="#Bookmark2663"><b>!rpcexts.getdbgcell</b></a> extension with the cell number in the THRDCELL column. This would allow you to examine the thread IDs so you could determine which call you were interested in.</p>
</li>
<li>After you know which call you are interested in, look at the cell number in the CONN/CLN column. This is the cell ID of the connection object. In this case, the cell number is 0000.0003. Pass this cell number and the process ID to <b>!rpcexts.getdbgcell</b>:<div class="code"><span codelanguage=""><table>
<tr>
<th></th>
</tr>
<tr>
<td>
<pre>0:001&gt; !rpcexts.getdbgcell 3d4 0.3
Getting cell info ...
Connection
Connection flags: Exclusive
Authentication Level: Default
Authentication Service: None
Last Transmit Fragment Size: 24 (0x6F56D)
Endpoint for the connection: 0x0.1
Last send time (in seconds since boot):10595.565 (0x2963.235)
Last receive time (in seconds since boot):10595.565 (0x2963.235)
Getting endpoint info ...
Process object for caller is 0xFF9DF5F0</pre>
</td>
</tr>
</table></span></div>
</li>
</ol>
<p>This extension will display all the information available about the client of this connection. The amount of actual information will vary, depending on the transport being used.</p>
<p>In this example, local named pipes are being used as the transport and the process object address of the caller is displayed. If you attach a kernel debugger (or start a local kernel debugger), you can use the <a href="#Bookmark2417"><b>!process</b></a> extension to interpret this process address.</p>
<p>If LRPC is used as the transport, the process ID and thread ID of the caller will be displayed.</p>
<p>If TCP is used as the transport, the IP address of the caller will be displayed.</p>
<p>If remote named pipes are used as the transport, no information will be available.</p>
<div class="alert"><b>Note</b>    The previous example shows how to find the client thread if you know the server thread. For an example of the <u>reverse</u> technique, see <a href="#Bookmark1443">Analyzing a Stuck Call Problem</a>.</div>
<div> </div></div></div>	
	<div id="winchm_template_footer">Copyright &copy; 2019. All rights 
reserved. (To change the copyright info, just edit it in template.)</div>
</div>

</body>
</html>
